Dynamics and anthropogenic impacts of multiple karst flow systems in a mountainous area of South China
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- 作者：Mingming Luo ; Zhihua Chen ; Robert E. Criss ; Hong Zhou ; He Huang…
- 关键词：Karst ; Hydrogen ; oxygen isotope ; Hydrochemistry ; Tracer test ; China
- 刊名：Hydrogeology Journal
- 出版年：2016
- 出版时间：December 2016
- 年：2016
- 卷：24
- 期：8
- 页码：1993-2002
- 全文大小：
- 刊物类别：Earth and Environmental Science
- 刊物主题：Hydrogeology; Hydrology/Water Resources; Geology; Water Quality/Water Pollution; Geophysics/Geodesy; Waste Water Technology / Water Pollution Control / Water Management / Aquatic Pollution;
- 出版者：Springer Berlin Heidelberg
- ISSN：1435-0157
- 卷排序：24
文摘
The Xiangxi River basin, South China, is a steep terrane with well-developed karst features and an important Cambrian-Ordovician aquifer. Meteoric water in this mountainous area features a mean δ18O elevation gradient of –2.4 ‰/km. This gradient was used to estimate mean recharge elevations of 760 m for Shuimoxi (SMX) spring, 1,060 m for Xiangshuidong (XSD) spring, and 1,430 m for drill hole ZK03, indicating multiple flow paths in the Cambrian-Ordovician karst aquifer. Mean residence times of 230 and 320 days and ∼2 years were estimated for these features, respectively, using the damped running average model that predicts the isotopic variations in groundwater from those in precipitation. Groundwater in the regional karst flow system has the longest residence time, the highest recharge elevation, the longest flow paths, the lowest addition of anthropogenic components, and the greatest amount of water–rock interaction as indicated by its higher dissolved solids, Mg2+ concentrations and Mg/Ca ratios than the springs. In contrast, the local and shallow karst flow systems respond rapidly to recharge events. Artificial tracer tests prove that these shallow karst systems can also quickly transmit anthropogenic contaminants, indicating that they are highly vulnerable to human impacts, which include the enrichment of NO3–. The intensity of water–rock interaction and groundwater vulnerability are mainly determined by the structure and dynamics of the multiple karst flow systems.